feat(selene): add PECOS general noise error-model plugin

[qciaran]

Summary

• add a device-neutral Selene error-model plugin backed by PECOS GeneralNoiseModel
• expose immutable GeneralNoiseParameters with the full configurable Rust builder surface and noiseless defaults
• bridge scheduled Selene operations, idle timing, leakage, crosstalk, metrics, and state dumps into PECOS
• register the package in Cargo/uv workspaces and the cross-platform wheel matrix

Validation

• 13 Python tests, including Stim and PECOS StateVec integration
• 2 Rust unit tests
• cargo clippy -D warnings
• cargo fmt and Ruff checks
• uv lock check
• wheel build with bundled native library